Seminar presentationEVOLUTION OF EDGEWISE
Under the guidance of :
Dr. Mohammad Mushtaq,
HOD & GUIDE
2nd Year P.G.
Department of Orthodontics & Dentofacial Orthopaedics, GDC&H, Srinagar.
3. Evolution of the technique
4. Merrifield contribuation.
• Edward Angle.
• Charles Tweed.
• Levern Merrifield.
The edgewise arch mechanism was
the brain child of this master
Edward Angle, after graduation
from dental school in
1878 and before his introduction of
the Angle System in
1888, experienced many technical
problems and frustrations
in patient treatment that motivated
him to develop a standard
He believed that an orthodontic appliance must have five
1. Simplicity: It must push, pull, and rotate teeth.
2. Stability: It must be fixed to the teeth.
3. Efficiency: It must be based on Newton’s third law
4. Delicacy: It must be accepted by the tissues, and it
must not cause inflammation and
5. Inconspicuousness: It must be aesthetically
• This was the beginning of a relationship among
manufacturers, suppliers, and orthodontists.
• Angle developed the edgewise appliance from the
ribbon arch mechanism and called it the open bracket
• Because Angle introduced the edgewise bracket only 2
years before he died, he had little time to teach its
manipulation, develop it further, and improve its use—
and he knew it.
When Charles H. Tweed graduated from an
Angle course given by George Hahn in
1928, he was 33 years old and Angle was 73.
Angle decided that an article describing the
appliance must be published in Dental
Cosmos. He asked Tweed
to help him with the article because Tweed
had just finished the Angle “course” and
because he admired and respected Tweed’s
• For the next 2 years the two men worked together
closely. Tweed diagnosed, treatment planned and treated
his patients, and Angle acted as his advisor. Angle was
pleased with the results, and he was instrumental in
getting Tweed on several programs.
• During these 2 years, in a series of more than 100 letters,
which are now housed in the Tweed Foundation Library,
Angle urged his young disciple to carry out two vital
• (1) to dedicate his life to the development of the
edgewise appliance and
• (2) to make every effort to establish orthodontics as a
specialty within the dental profession.
• His untiring and relentless efforts were successful, and
in 1929 the Arizona legislature passed the first law
limiting the practice of orthodontics to specialists.
• Tweed received Certificate No. 1 in Arizona and became
the first certified specialist in orthodontics in the United
• In 1932, Tweed published his first article in the Angle
Orthodontist. It was titled “Reports of Cases Treated with
Edgewise Arch Mechanism.”3 Tweed held to Angle’s
firm conviction that one must never extract teeth. This
conviction lasted for 4 short years.
• The postreatment facial aesthetics Tweed began to observe
in his patients was discouraging to him, so discouraging in
fact that he almost gave up orthodontic practice.
• During this 4-year period, he made a most important
observation: upright mandibular incisors frequently were
related to both posttreatment facial balance and stability of
the treated dentition. He selected his failures, extracted
four first premolar teeth, and retreated the patients. He did
this without charging a fee.
• In 1936 Tweed delivered to the membership of the Angle
Society and subsequently published his first paper on the
extraction of teeth for orthodontic malocclusion correction.
“Mother” Angle, the editor of the Angle Orthodontist and a
member of the Angle Society, refused to attend the lecture.
• He worked even
harder than before.
By 1940, he had
reports, with four
sets of records, of
treated patients who
were first treated
and later with
• Tweed’s many contributions to the specialty established
a benchmark in orthodontic thought and treatment.
Most notable among his many contributions were the
1. He emphasized the four objectives of orthodontic
treatment—aesthetics, health, function, and stability—
with emphasis and concern for balance and harmony of
the lower face.
2. He developed the concept of positioning teeth over basal
bone with emphasis on the mandibular incisors.
3. He made the extraction of teeth for
4. He enhanced the clinical application of
5. He developed the diagnostic facial triangle
to make cephalometrics a diagnostic tool and
a guide in treatment and in the evaluation of
6. He developed a concept of orderly
treatment procedures and introduced
anchorage preparation as a major step in
7. He developed a fundamentally sound and
consistent preorthodontic guidance program
that popularizied serial extraction of primary
and, later, permanent teeth.
Charles Tweed, one of orthodontics’ most brilliant
innovators, kept his promise to his mentor,
Edward Hartley Angle. He devoted 42 years of his
life, from 1928 until his death on January 11, 1970,
to the advancement of the edgewise appliance
• In 1960 Tweed selected one of his
most outstanding students, Levern
Merrifield, from Ponca
City, Oklahoma, to continue his
work on the edgewise appliance.
• Merrifield devoted the remaining
45 years of his life to the study of
orthodontic diagnosis and the use
of the edgewise appliance.
Merrifield’s contributions have
been disseminated and
ANGLE’S PHILOSOPHY OF
• Based on the then prevalent assumption that, if
cuspal interdigitation of teeth were made normal,
stimulation by function would result in growth of
basal bone structures.
• Little or no thought was given to the inclination of
the mandibular incisor teeth or to normal
mesiodistal relation of teeth and their respective
jaw bases and head structures.
• It was assumed that function would take care of
• Extraction of teeth for orthodontic therapy wasn’t
even an option .
Evolution of the appliance
• First attempt at tooth movement
in1728 by a French physician
• Bandalette appliance-crude
alignment of teeth by expansion
of the dental arches.
• Disadvantage : lacked stability
no effective means of firmly
fixing it in position
• 1841-Schange introduced screw force.
• 1849-Dwinelle developed jack screw.
• 1871-Magil introduced dental cements to attach bands
• 1866-Kingsley advocated the use of extra oral forces .
• No attempt was made to correct malocclusion by
placing teeth in a stable soft tissue environment .
• Angle believed that teeth when moved into their
correct occlusal relationship, stability would be
The E arch appliance(1880)
• First typical orthodontic
fixed appliance Rigid
framework –Molar bands
with heavy labial arch
wire soldered to them,
Teeth tied to it by means
of brass ligature wire
Crown movement &
simple anchorage Teeth
were expanded into
4 different designs:
E-arch without threaded ends that fit into
molar sheaths, used with an attached ball
for high pullheag gear in the incisor area.
• E-arch with hooks for intermaxillary
elastics. Also had maxillo mandibular
• Disadvantages :1) correction of axial
inclination could not be accomplished
2)long term retention was required.
The Pin &Tube appliance(1912)
• Ideal arch of E-arch was not
there. Arches were altered as
tooth movement carried out
progressing towards ideal
archform .Bands with tubes
soldered on it .Pins soldered on
the archwire & made to fit into
tube perfectly .Change position
of pin ,solder it again on
archwire to a different position &
fit into the tube again .
• Disadvantage:difficult to solder
& unsolder pins time consuming
Ribbon arch appliance (1915)
• To overcome disadvantage of
pin & tube Brackets with
vertical slot introduced
Archwire initially confirmed
to malocclusion ,held in place
by brass pins Rectangular
wire with longer dimension
vertical Overcame 2 major
1) archwire placement
2) M-D movement of teeth Teeth
were free to move along the
archwire like strings of beads.
• Teeth could tip M-D, even with lockpins
Angle devised cleats to be soldered to
archwire to contact the sides of the bracket
Held the teeth upright, but necessitates
soldering new cleats at different locations.
• Disadvantage:-relatively poor root control mesial & distal tipping bends could not be
incorporated -enmass movement of teeth in
an anteroposterior direction was not easy
The Edgewise appliance(1925)
• Solution to all problems –
latest & best in orthodontic
Changed the form of bracket
located the slot in the center &
placed it in a horizontal plane
instead of a vertical.
Bracket wide mesio-distally
Rectangular slot for rectangular
archwire .022x.028 slot size,
same size Archwire inserted in
narrowest dimension EDGEWISE .
Initially called open face or tie
brackets Archwire held with
brass ligature & S-S ligature.
Evolutionof edgewise brackets
Original bracket-soft gold , .022 x
.028 inch slot.
1)Single width brackets:
original bracket .050 inch wide &
soldered to the gold band material
archwire rests on bottom of bracket
slot instead of the band ineffective
for tooth rotation because of the
narrow width Angle devised gold
eyelets to be soldered on bands.
•2)Twin brackets - two brackets on one
base -“Siamese twin brackets” by
space between two brackets was .050
inch (equal to width of one bracket )
Main advantage : - ability to effect
tooth rotations without using
auxiliaries Available in different
3)Curved base twin
curved bases to confirm to
the curvatures of the
canines & premolars
• Advantages of twin
brackets : Offers a
• 4)Lewis bracket
• Developed by Lewis in 1950. To
overcome the problem of efficient
tooth rotation. He soldered
auxillary rotation arms that
abutted against the bracket itself,
thus, offered a lever arm to deflect
the archwire & rotate the tooth.
One piece bracket with integral
rotation wings.These wings do
not interfere with occlusogingival
deflections of archwire & do not
decrease the interbracket span.
5. Curved base Lewis
base confirms to the
canine, premolar surface
Wings lie close to the
tooth throughout their
length ,so less trapping of
• 6)Vertical slot Lewis bracket:
Incorporation of .020 x .020 inch vertical
slot Possible to use uprighting spring to
correct axial inclinations if needed.
Advantages of Lewis brackets:
1) complete rotational control
2)do not reduce the interbracket span
7) Steiner bracket Given by Cecil C Steiner in
Incorporated flexible rotation arms & so did
not rely on the resiliency of the archwire for
tooth rotation Introduced tie wings for ease of
8)Broussard bracket :
Designed by Garford Broussard for use in the
Broussard technique. Addition of a 0.0185 x
0.046 inch vertical slot to accept a doubled
0.018 inch auxillary.
Evolution of edgewise buccal
• Original appliance had .022x .028 inch gold
or nickel silver tubing soldered to the molar
band Length –3/16 or ¼ inch. Notched distal
ends - to facilitate a tie back ligature Hook –
gingival to buccal tubes, soldered on the
bands for placement of elastics. Inconel tube gold buccal tubes were discarded. Stamped
buccal tube with welding flanges or Inconel
tube which could be soldered to the band .
• Combination buccal tubes :
Incorporates a round tube for
insertion of a face bow. Fairly
close tolerances must be
maintained between archwire &
tube for effective transmission
of torque to the tooth.
• Triple buccal tube additional
rectangular tube for auxillary
sectional & base archwire.
Bracket & tube placement.
• Angle, “goal of correct bracket & tube
placement is to produce an ideal occlusion
at the end of treatment with flat, straight,
• Tweed advocates – millimeter
measurement from bracket slot to the
UPPER ARCH Centrals –4.5
Anteriors-4.0 Canines4.5 Premolars-5.0
• Brackets –parallel to the long
axis of the tooth
• Holdaway (1952) described three
uses for bracket angulation
a) as an aid in paralleling roots
adjacent to extraction spaces.
b) as a method of setting up
posterior anchorage units into
tipped back or anchorage prepared
c) as a means of obtaining correct
axial inclinations or artistic
• The dimensions (in inches) of the wire
commonly used are 0.017 × 0.022, 0.018 ×
0.025, 0.019 × 0.025, 0.020 × 0.025, and 0.0215 ×
• These wire dimensions give a great range of
versatility with the 0.022 × 0.028 bracket slot
and allow the sequential application of forces
as needed for various treatment objectives.
The objective is to enhance tooth movement
and control with the proper edgewise
archwire at the appropriate time.
Evolution of technique
Primary edgewise as described by Angle in 1929.
Fully banded technique-gold bands ,soldered soft brackets.
flat ideal arch wire -to provide normal occlusion.
Original arch was of .022 X .028 inch gold wire to be
adapted passively to all malocclusion.
If space had to be made, loops are soldered onto main arch.
If space closure required, spurs & tie backs used.
Involves all the teeth to be brought under control so,
treatment should be initiated after eruption of canine &
Angle stated that "malocclusion must be treated as
though the denture is a self-sustaining, self
maintaining unit and all parts of denture exerting or
sustaining forces must be perfectly balanced”
1) fully normal proximal contact relations of teeth
2) normal cusp & inclined plane relation
3) normal upright axial position & relation of teeth
this is essential if the teeth are to balance with the
muscles & sustain the forces of occlusion.
To avoid the making archwires passive.
Use of round wires in the initial stages.
Gold was replaced by a more rigid alloy.
Frequency of extractions increased.
Bands with prewelded brackets.
In 1940s round .045in.tubes were also
soldered on the upper molars for a face
Tertiary edgewise or Tweed’s
Stressed on the importance of anchorage
preparatio,. advocated the use of class III
elastics & extraoral traction vigorous forces
were now employed.
Space closure was done by simple vertical or
horizontal open loops bent into the archwire
or by push coil tie .
1. The fundamental concept of dimensions of the
2. Dimensions of the lower face.
3. Total space analysis.
4. Guidelines for space management decisions to
a. Maximum orthodontic correction
b. Define areas of skeletal, facial, and dental
5. Directional force control during
6. Sequential tooth movement
7. Sequential mandibular anchorage
8. The organization of treatment into four
orderly steps that have specific objectives.
Variations of the Appliance
Many variations of the edgewise appliance
have been introduced in the past 30 years.
• Most notable of the variations is the
“straight wire” appliance introduced in
1972 by Larry Andrews.
• Another variation is a decrease in slot size
from 0.022 to 0.018 inch and even to 0.016
• Other modifications have been extensively
described by Burstone, Lindquist,
Angle gave orthodontics the edgewise
bracket, but Tweed gave the specialty the
appliance. Tweed was considered the
premier edgewise orthodontist of his day.
Many who admired his results wished to
learn his techniques.
The Tweed Philosophy was born.
In summary, Tweed's basic concepts were:
(1) a deep and abiding interest in facial esthetics;
(2) Carefully planned extractions to achieve a
predetermined objective. To arrive at the
predetermined objective, Tweed had to define the
anterior limits of the dentition. He developed the
diagnostic facial triangle for this purpose;
(3) precision appliance adjustment; and
(4) en masse anchorage preparation.
The orthodontic world beat a path to his door in Tucson.
Tweed, the innovative and perceptive diagnostician and
master clinician, kept his promise to his mentor, Edward
He devoted all 42 years of his professsional life to the use
and refinement of Angle's invention, the edgewise
Tweed's last great work, the two volume
Clinical Orthodontics, is inscribed
"To Dr. EdwardHartley Angle, a dynamic
psychologist with the power to mold the
character of men; to his devoted wife, Anna
Hopkins (Mother) Angle,who guided his
career and bathed the wounds of those
undergoing his molding procedures;
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